Mercury switch relay



July 24, 1934.

cfH. LARSON 1,967,951

MERCURY swiTcH RELAY Fil d May l5 1953 Patented July 24, 1934 MERCURY SWITCH RELAY Carl H. Larson, Elkhart, Ind., assignor to The Adlake Company, a. corporation of Illinois Application'May 15, 1933, Serial No. 671,047 21 Claims. (Cl. 200112) The subject matter of this application is disclosed but not claimed in my copending applications 636,286 and 656,781, filed October 5, 1932 and February 15, 1932, respectively.

5 The invention relates to mercury switch relays and has for its principal object to provide a mounting for one or more mercury switches in which the magnetic circuit bears such relationship to the switch elements as to result in highly l eflicient operation of the relay.

Further and other objects and advantages will become apparent as the disclosure proceeds and the description is readin conjunction with the accompanying drawing, in which Fig. 1 is a perspective view of the complete iron circuit;

Fig. 2 illustrates an application of the iron circuit to a single switch relay of the back contact type;

20 Fig. 3 is a fragmentary, sectional view corresponding to Fig. 2, but showing a front contact switch mounted in the coil;

Fig. 4 is a plan view of a multi-switch relay made in accordance with this invention;

Fig. 5 is a sectional view taken on the line 5 -5 of Fig. 4; and V Fig. 6 is a perspective view of the two-part yoke that is used in the multi-switch relay.

It will be understood that the illustration of 30 preferred forms of the invention and the specific description that follows are for the purpose of description only and neither should be interpreted as imposing limitations upon the appended claims except as required by the prior art.

Single switch relay The single switch relays shown in Figs. 2 and 3 illustrate the application of the iron circuit of Fig. l to a relay employing but one circuit breaker.

The circuit breaker 10 of the back contact relay (Fig. 2) consists of a vertical glass envelope 11 into the base of which electrodes 12 and 13 are sealed. The electrode 12 is insulated to a point adjacent its top by aglass sleeve 14.

electrical circuit through the electrodes 12 and 13 according to the level of the mercury.

For best results, the envelope should be made of glass having a high melting point and a low coefiicient of thermal expansion, such for example as the glass specified in Weintraub Patent No. 1,154,081. It is also preferred that the glass should be substantially free from compounds of lead, tin, antimony, and other substances which are de- A quantity of mercury 15 is placed in the envelope and is adapted to make or break an composed by the action of an electric arc. The electrodes 12 and 13 may be made of tungsten, molybdenum, tantalum, or any other electrode material having suitable properties of thermal expansion and fusibility with the particular glass 0 used in the envelope.

A displacer or plunger 16 of magnetic material telescopes over the central electrode 12 and determines the level of the mercury. In theposition shown in Fig. 2, the operating coil, generally 65 designated 17 is de-energized, but when energized the displacer is lifted a suflicient amount to cause the mercury level to recede below the top of the insulating sleeve 14 and thereby break the electrical circuit through the electrodes 12 and 13. When the coil is again de-energized, the displacer falls by its own weight to the position shown in Fig. 2 and the circuit is re-established. An inert gas is used in the envelope 11 to suppress the electric are which tends to form be- 76 tween the electrode 12 and the mercury when the circuit is being closed or opened. The 'gas fill may be pure hydrogen, helium, a physical combination of the two, helium hydride, or any other suitable gas fill known to the art. After the gas fill has been introduced into the envelope, the latter is sealed oil as indicated at 18.

The displacer 16 is preferably provided with lugs 19 to guide its movement within the envelope. v

Theswitch 10 is supported in the coil 1'7 by the iron or magnetic circuit, generally designated 20. It consists of pole sleeves 21 and 22 of suitable material such as Swedish iron, whichv are held firmly by clips 23 against the legs 24 and 25', respectively, of a yoke 26. The yoke is made up of a plurality of laminations each consisting of a sheet of magnetic material, such as iron, cut in channel form with a vertical portion terminating v inthe laterally extending leg portions or pole pieces 24 and 25. The laminations are held together by rivets 27 or by any other suitable means. The ends of the legs 24 and 25 are rounded, as shown in Fig.1 to conform to the periphery of the sleeves 21 and 22 so that there is a uniform 10o contact between the legs and the sleeves. The clips 23'are secured to the yoke by screws 28 or equivalent means.

Preferably the sleeves 21 and 22 are each provided with a longitudinal slit 29 which materially 1 5 increases the efliciency of the relay when operating on alternating current. The slits apparently have the effect of preventing induced electrical currents from travelling in a circular path around the sleeves.

l'he sleeves 21 and 22 are separated by an air gap 30 which is positioned adjacent the top of the displacer. The actual air gap includesin addition to the space mparating the sleeves, the thickness of the glass envelope and the distance which separates the displacer from the envelope.

In the front contact relay shown in Fig. 3, the switch 31 has a longer central electrode 32 and the displacer 33 is substantially lighter than the displacer 16 or the back contact relay of Fig. 2. Also in this case, the air gap 34; which separates the upper and lower pole sleeves 35 and '36, respectively, is positioned somewhat lower so that when the coil 1? is energized, the displacer 33 will move downwardly in its eiicrt to close the air gap 34.

The iron circuit used with the front contact relay of Fig. 3 is otherwise identical with the one shown in Figs. 1 and 2.

One advantage in constructing a single switch relay in this manner is that there is .always an air gap corresponding to the thickness of the glass envelope separating the displacer from the pole sleeves. In mechanical relays, trouble is often encountered because residual magnetism will hold an armature against the coil even after the latter has been de-energized, but this is virtually impossible in the present type of relay. The constant air gap represented by the thickness of the glass envelope effectively prevents relay failure due to residual magnetism.

The pole sleeves. have another function in addition to fixing the position of the air gap. Since they surround the envelope, the magnetic flux is distributed on all sides of the displacer so that there is no tendency for the displacer to be attracted more strongly on one side than on another.

The pole sleeves are adjustable lengthwise within the clips 23 for fixing the position of the air gap. I The switch envelopes are held in fixed relation to the coil 17 and the magnetic circuit by a split sleeve 37 of non-magnetic material possessing sufilcient resiliency to frictionally engage the envelopes and hold them against vertical movement. When suficient force is applied, the envelope may, of course, be slid past the sleeve 37. Bakelite or brass have been found to be suitable material for the sleeve 37.

MuZti-smtch relay of current to another.

Referring to Fig. 4, the switches are identified by the letters A, B, C and D, and each consists of a vertical glass envelope having a displacer movable in response to the coil to change the mercury level and hence determine the condition of the circuit through the electrodes. For the purpose. of this disclosure, switches A and B may be front contact switches of the type shown in Fig. 3 and switches C and D may be back contact switches of the type shown in Fig. 2.

. The coil 38 in the multi-switch relay comprises a spool of insulating material upon which copper wire 39 is wound. The spool has a central opening 4a which in this instance is substantial y. square, for reasons which will later appear.

accuser The iron circuits associated with the switches A, B, C and D are identical in every respect with the iron circuit shown in Fig. 1 with the exception that the yoke 26 is made in two parts to enable the relay to be assembled. The yoke may be divided in many ways for this purpose, but preferably the laminations are stamped in two forms: In rectangular form for that portion of the yoke indicated at 4.1 and in L-shaped form for that portion of the yoke indicated at 4.2.

The several iron circuits are assembled together in the coil, as shown in Figs. 4 and 5, with the vertical portions of the yoke passing through the opening 4.0, and with the leg portions or pole pieces extending radially to support the switches in a vertical position parallel to the coil. Each switch, therefore, has associated with it an iron circuit that passes through the coil and is closed except for an air gap that is positioned in proper relation to the armature or plunger of the switches.

Obviously, any number of switches may be mounted on a single coil by suitably shaping the central opening of the coil and by shaping the yokes accordingly. It is not essential that the portions of the yokes passing through the coil fill the opening completely, or fit together in compact form, but it is preferred, as greater efficiency is obtained by such an' arrangement.

What I claim, therefore, is: i

1. In a. mercury switch relay, a coil, a'plurality of mercury switches adapted to be operated from said coil, said switches being mounted parallel to the coil and substantially radially thereof, and each comprising a switch envelope, a quantity of mercury in the envelope adapted to make or break an electrical circuit through the electrodes according to its level, a displacer movable within the envelope to change the mercury level, said displacer including magnetic material whereby it is shifted in response to the coil.

2. In a mercury switch relay, a coil, a plurality of mercury switches adapted to be operated from said. coil, said switches being mounted parallel to the coil and substantially radially thereof and each including a displacer shiftable in response to the coil.

3. In a mercury switch relay, a coil, 9. plurality of mercury switches mounted parallel to and substantially radially of said coil, each including an armature movable in response to the coil, and iron circuits associated with each switch and having an air gap in the vicinity of the armature.

c. In a device of the class described, an electromagnet having a spool of polygonal cross section, and a, plurality of tube supporting core pieces mounted in the spool and having legs projecting radially from the spool.

5. A multi-switch relay, comprising a magnet coil, a. plurality of radially extending pole pieces.

projecting to the margin of the coil, and mercury switches supported at the ends of the pole pieces.

6. A multi-switch relay comprising a magnet coil having a spool, a plurality of L-shaped pieces mounted in the top and bottom of the spool with their legs projecting radially. to the margin of the coil and with the bottom legs alined with the top legs, and mercury switches mounted between said upper and lower legs.

'7. In a mercury switch relay, a coil having a hollow core, a plurality 'of mercury switches mounted parallel to and substantially radially of the coil, each including an armature movable in respoh fi 0 the coil and an iron magnetic circuit associated with one of the switches, said iron circuit passing through the core and having an air gap in the vicinity of said armature.

8. In a mercury switch relay, a coil having a hollow core, a plurality of mercury switches mounted parallel toand substantially radially of the coil, each including a switch envelope, an armature movable in response to the coil and an iron magnetic circuit associated with one of the switches, said iron circuit including spaced pole sleeves telescoped over the switch envelope to define an air gap'in the vicinity of the armature.

9. In a mercury switch relay of the type in which a displacer is magnetically shifted within a sealed envelope for changing the mercury level thereby to make or break an electrical circuit through the spaced electrodes, the combination therewith of means including pole pieces for setting up a vertical magnetic fieldthrough the envelope, and a pole sleeve of magnetic material telescoped over the envelope and extending from one pole piece in the direction of the other to fix the position of the air gap with respect to the displacer.

\ 10. In a mercury switch relay of the type in which a displacer is magnetically shifted within a sealed envelope for changing the mercury level thereby to make or break an electrical circuit through the spaced electrodes, the combination therewith of means for sett' up a vertical magnetic field through the envelope, and longitudinally split pole sleeves of magnetic material tele scoped over the envelopeand fixing the position of the air gap with respect to the displacer.

11. In a mercury switch relay of the type in which a displacer is magnetically shifted within a sealed envelope for changing the mercury level thereby to make or break an electrical circuit through the spaced electrodes, the combination therewith of means including pole pieces for setting up a vertical magnetic field through the envelope, a pole sleeve of magnetic material te1escoped over the envelope and extending from one pole piece in the direction of the other to fix the position of the air gap with respect to the displacer, and a yoke of magnetic material having its ends adjacent to the pole pieces.

12. In a mercury switch relay of the type in which a displacer is magnetically shifted within a sealed envelope for changing the mercury level thereby to make or break an electrical circuit through the spaced electrodes, the combination therewith of means including pole pieces for setting up a vertical magnetic field through the envelope, pole sleeves of magnetic material telescoped over the envelope and fixing the position of the air gap with respect to the displacer, a yoke of magnetic material having its ends adjacent to the pole pieces, and clips embracing the pole pieces to hold them in proper spaced relation.

13. In a mercury switch relay of the type in which a displacer is magnetically shifted within a sealed envelope for changing the mercury level thereby to make or break an electrical circuitthrough the spaced electrodes, the combination therewith of means for setting up a vertical magnetic field through the envelope, and a yoke of magnetic material projecting laterally from the envelope and having its legs one above the other abutting the upper and lower portions of the envelope, said yoke having a solid portion of substantial cross section connecting the top and bottom legs of the yoke.

14. In a mercury switch relay of the type in which 5 displacer is magnetically shifted within a sealed envelope for changing the mercury level thereby to make or break an electrical circuit through the spaced electrodes, the combination therewith of means for setting up a vertical magnetic field through the envelope, and a yoke of magnetic material projecting laterally from the envelope and having its legs one above the other abutting the upper and lower portions of the envelope, said yoke being laminated in planes parallel to the magnetic flux.

15. For use in a relay of the class described, a yoke of magnetic material comprising a plurality of thin sheets cut to similar configuration, each comprising a vertical portion terminating in leg portions extending laterally one above the other from the vertical portion, and means for clamping said sheets together.'

16. In a mercury switch relay of the type in which a displacer is magnetically shifted within a sealed envelope for changing the mercury level thereby to make or break an electrical circuit through the spaced electrodes, the combination therewith, of a solenoid telescoped over the envelope for controlling the displacer, and a yoke of magnetic material connecting the top and bottom of the envelope exteriorly of the solenoid.

17. In a mercury switch relay of the type in which a displacer is magnetically shifted within a sealed envelope for changing the mercury level thereby to make or break an electrical circuit through the spaced electrodes, the combination therewith of a solenoid telescoped over the envelope for controlling the displacer, pole sleeves of magnetic material interposed between the solenoid and the envelope for fixing the position of the air gap with respect to the displacer, and a yoke of magnetic material exteriorly connecting the envelope above and below the air gap.

18. In a mercury switch relay of the type in which a displacer is magnetically shifted within a sealed envelope for changing the mercury level thereby to make or break an electrical circuit through the spaced electrodes, the combination therewith of means for setting up a vertical magnetic field through the envelope, and a yoke of magnetic material projecting laterally from the envelope and having its legs one above the other abutting the upper and lower portions of the envelope, said yoke being formed of separable halves, whereby the portion joining the legs may 125 be inserted in a coil.

19. In a mercury switch relay of the type in which a displacer is magnetically shifted within a sealed envelope for changing the mercury level thereby to make or break an electrical circuit through the spaced electrodes, the combination therewith of means for setting up a vertical magnetic field through the envelope, and pole sleeves of magnetic material telescoped over the envelope and fixing the position of the air gap with respect to the displacer, said pole sleeves being adjust- 4 able whereby the position of the air gap may be accurately determined.

20. In a mercury switch relay of the type in which a displacer is magnetically shifted within a sealed envelope for changing the mercury level thereby to make or break an electrical circuit through the spaced electrodes, the combination therewith of means for setting up a vertical magnetic field through the envelope, and an iron path of substantial cross section for the magnetic .field, closed except for an air gap adjacent one wev ee a sealed envelope m2 elmengmg the merelnry level thereby to make er lax-eel: em electrical elrcmt through the spewed electrodes, the eemlolmtlon therewith of means for setting up a vertteel m netic field through the envelope, and an item path of substantial emcee section 13m the meg metlc flelol, closed except Ker em all? {yep adjacent CARL SUN. 

